1. Field
Example embodiments relate to memory devices and methods of manufacturing the same. More particularly, example embodiments relate to vertical memory devices having a vertical channel and methods of manufacturing the same.
2. Description of the Related Art
During the manufacturing of a vertical memory device, an insulation layer and a sacrificial layer may be alternately and repeatedly formed on a substrate. Holes are formed though the insulation layers and the sacrificial layers. Channels are formed in the holes. Openings are likewise formed through the insulation layers and the sacrificial layers. The sacrificial layers exposed by the openings are removed to form gaps that expose the channels. Oxide-nitride-oxide (ONO) layers and gate structures including gate electrodes are formed in the gaps.
The holes typically have a width that becomes gradually smaller from a top portion to a bottom portion thereof, due to the characteristics of an etch process. Therefore, memory cells disposed at the top portion and the bottom portion of the hole, respectively, may have different sizes and different electrical characteristics.